online ML Comm LABORATORY INVESTIGATION J Kor Neurotraumatol Soc 27;3:91-98 ISSN 1738-878 뇌피질충격기구를이용한뇌외상동물모델제작 아주대학교의과대학신경외과학교실, 신경재생줄기세포연구소 김화정 김세혁 안영환 Animal Model of Traumatic Brain Injury Induced by Controlled Cortical Impact Device Hwa-Jung Kim, Se-Hyuk Kim, MD, PhD and Young-Hwan Ahn, MD, PhD Department of Neurosurgery, Institute for Neuroregeneration and Stem Cell Research, Ajou University School of Medicine, Suwon, Korea Objective: The goal of this study is to evaluate the structural and behavioral changes according to different impact velocities and different deformation depths in the rat controlled cortical impact (CCI) model. Methods: Male Sprague- Dawley rats (25-3 g) were anesthetized and traumatic brain injury (TBI) was induced by impacting the cerebral cortex using a pneumatic CCI device at the different velocities and injury depths. One day after TBI, the neurological function was assessed and then the injured area of cerebral cortex and hippocampus was measured. Results: With a 3.2 or 3.9 m/s of impact velocity, there was a significant decrease in rotarod motor score at 2.5 mm of deformation depth compared to 1.5 mm, and the injured area of cortex was increased significantly at 2. or 2.5 mm of depths compared to 1.5 mm. The injured area of hippocampus was significantly increased at 2.5 mm of depth with a 3.2 m/s of velocity and 2. or 2.5 mm of depths with a 3.9 m/s of velocity, compared to the other deformation depths. For the same deformation depth, only the injured area of hippocampus was significantly different between each velocity with a 2. mm of depth. Conclusion: This study presented the neurological and morphological changes according to the various deformation parameters in the rat CCI model. We expect that our results will provide a guideline in determining those parameters for reproducible gradation of rat CCI injury. (J Kor Neurotraumatol Soc 27;3:91-98) KEY WORDS: Animal model Traumatic brain injury Controlled cortical impact Injury severity. 서 론 인간의뇌외상은일단사고가발생하게되면이차적인뇌손상을유도하여뇌세포의영구적인기능소실을초래할수있으나, 손상된뇌기능자체를회복시킬수있는뚜렷한치료법은현재까지개발되고있지않다. 효과적인뇌외상치료제개발을위해서는외상후발생되 Address for correspondence: Se-Hyuk Kim, MD, PhD Department of Neurosurgery, Institute for Neuroregeneration and Stem Cell Research, Ajou University School of Medicine, San 5 Woncheon-dong, Yeongtong-gu, Suwon 443-749, Korea Tel: +82-31-219-5236, Fax: +82-31-219-5238 E-mail: nsksh@ajou.ac.kr 본논문의요지는 26 년제46 차대한신경외과추계학술대회에서포스터로발표되었음. 본연구는보건복지부보건의료기술진흥사업 ( 과제번호 : 412-DB-11-7) 과 BK21 세포변형및재생연구사업단의지원에의하여이루어진것임. 는병리학적소견과기능적변화를인간의경우와유사하게반복적으로재현할수있는실험모델제작이필수적이다. 그동안알려진실험동물에서의여러가지뇌외상모델중유체충격 (fluid percussion) 모델의경우외상기전자체는인간의두부외상기전과흡사하다. 하지만, 손상을유발한변수 (parameter) 의정도를정확히측정하기위한역학적인분석이어렵다는단점때문에재현성이중요한실험모델로서는한계가있고, 심한손상을유발시킬경우에는주로뇌간부위에손상을유발하는것으로알려져있다. 12) 유체충격모델에비하여뇌피질충격기구 (controlled cortical impact device) 를이용한실험모델은뇌손상을유발하는변수를조절하여손상정도를제어하는것이비교적용이하면서, 뇌외상유발후발생되는병태생리학적기전이실제뇌외상환자에서와유사하게진행되기때문에뇌외상연구를위한 Copyright c 27 Journal of Korean Neurotraumatology Society 91
Animal Model of Controlled Cortical Injury 동물모델로써많이이용되고있다. 1,5,6,9,14,15) 그러나손상유발변수의정도에따른뇌손상강도에대한연구결과보고를문헌고찰상찾아볼수없었다. 본연구에서는뇌피질충격모델에서손상정도에영향을줄수있는충격속도와변형깊이를달리하여실험동물에서뇌외상을유발한후행동지수와병리학적손상정도를관찰하여외상유발변수의강도에따른기능적, 형태학적손상정도를확인을통해, 뇌외상동물모델제작에있어뇌손상정도를달리할수있는기준을제시하고자하였다. 대상및방법 뇌외상동물모델제작생후 8~1 주의수컷 Sprague-Dawley 백서 (25~ 3 g) 를뇌외상생성 3일전부터 rotarod treadmill (Ugo Basile, Italy) 을이용하여훈련시켰다. 18) 뇌외상생성당일실험동물을 isoflurane 을이용하여흡입마취시킨후두부를동물실험용뇌정위기구에고정시키고, 우측반구의 lambda 와 bregma 중간부위, 정중선에서 5 mm 외측을중심으로하여직경 8 mm 크기의두개골절제술을시행하여경막을노출시켰다. 경막을보존하면서압축공기를사용하는뇌피질충격기구 (Amscinece, USA) 를이용하여충격속도와변형깊이를달리하여뇌외상을생성하였다. 신경행동지수측정뇌외상 24시간후 rotarod motor test와 modified neurological severity score (mnss)(table 1) 11,13) 를이용하여실험동물의신경학적행동지수를측정하였다. Rotarod test 는 rpm에서시작하여 3초마다 5 rpm씩속도를증가시켜 3 rpm까지속도를높인후최장 5분동안측정하였다. 외상전 3일간의훈련을통해 5분간 rotarod test 를통과한실험동물만을사용하여외상을유발하였으며, 외상후 rotarod motor scores 는외상전에대한백분율로측정하였다. 또다른행동지수인 mnss 의경우운동능력, 감각기능, 평형유지력, 반사기능등을종합적으로평가하여점수화하였다. TABLE 1. Modified neurological severity scores (mnss) 11,13) Motor tests Raising the rat by the tail 3 1=Flexion of forelimb 1=Flexion of hindlimb 1=Head moved >1 to the vertical axis within 3s Walking on the floor (normal=; maximum=3) 3 =Normal walk 1=Inability to walk straight 2=Circling toward the paretic side 3=Fall down to the paretic side Sensory tests 2 1=Placing test (visual and tactile test) 1=Proprioceptive test (deep sensation, pushing the paw against the table edge to stimulate limb muscles) Beam balance tests (normal=; maximum=6) 6 =Balances with steady posture 1=Grasps side of beam 2=Hugs the beam and one limb falls down from the beam 3=Two limbs fall down from the beam or spins on the beam (>6 s) 4=Attempts to balance on the beam but falls off (>4 s) 5=Attempts to balance on the beam but falls off (>2 s) 6=Falls off: no attempt to balance or hang on to the beam (<2 s) Reflexes absence and abnormal movements 4 1=Pinna reflex (a head shake when touching the auditory meatus) 1=Corneal reflex (an eye blink when lightly touching the cornea with cotton) 1=Startle reflex (a motor response to a brief noise from snapping a clipboard paper) 1=Seizures, myoclonus, myodystony Maximum points 18 One point is awarded for the inability to perform the tasks or for the lack of a tested reflex. 13 18=severe injury; 7 12=moderate injury; 1 6=mild injury Points 92 J Kor Neurotraumatol Soc 27;3:91-98
Hwa-Jung Kim, et al. 예비실험본실험에서사용할뇌피질충격기구 (Amscience, USA) 의압축공기압력에따른충격속도를확인하고, 각각의압축공기압에따른뇌외상후행동지수의변화양상을알아보고자하였다. 예비실험군에두개골절제술만가한군, 압축공기압 5 psi와 2 mm의변형깊이로뇌손상을가한군, 압축공기압 8 psi 와 2 mm의변형깊이로뇌손상을가한군의 3군으로하여각실험군당 4마리에서뇌손상을유발한후 1주일간격으로 4 주간 rotarod motor score 와 mnss 를측정하였다. 각각의공기압에대한충격속도는 linear variable differential transformer 를이용하여아날로그신호를디지털신호로변화시킨후 Labscribe Data Acqusition Software (CB science, USA) 로계산하였다. 충격속도는프로그램상의 Impact Rod Position Waveform 에따른시간변량값 (Δt) 을입력하여다음공식에의하여계산하였다. 피스톤의이동거리는 5 cm로고정하였다. Average Speed=(full displacement.8)/δt (sec) Δt ; 1% to 9% of the full amplitude full displacement=5 cm 예비실험동물의광학현미경관찰 5 psi와 8 psi의충격속도와 2. mm의변형깊이로뇌손상을가한예비실험동물모델의병리학적뇌손상정도를확인하기위하여각각 3마리의실험동물을뇌외상후 1일째희생시켰다. 심장을통해생리식염수를관류하여혈액을제거한후, 4% paraformaldehyde 로조직내단백질을고정하고, 동결절편하여 cresyl violet 염색을하였다. 충격속도와변형깊이를달리한본실험예비실험을통해확인한각각의충격속도 3.2±.1 m/s ( 압축공기압 5 psi) 와 3.9±.1 m/s ( 압축공기압 8 psi) 에서변형깊이를 1.5 mm, 2. mm, 2.5 mm 로달리하여각실험군당 7마리씩, 총 6개실험군 42마리의실험동물에서뇌손상을유발하였다. 뇌외상 24시간후에 rotarod motor test와 mnss 측정을통하여실험동물의신경학적행동지수를확인하고실험동물을 isoflurane 을이용하여흡입마취시켜희생시킨후전뇌를적출하였다. 적출한전뇌를생리식염수로 2분간세척한후 rat brain matrix 를이용하여 2 mm 두께로절편하였다. 이후각각의절편을 6 well dish 에넣고, 3분간 1% 2, 3,5-triphenyl tetrazolium chloride (TTC) monohydrate (Sigma Chemicals, USA) 용액으로염색을한후, 2) 4% paraformaldehyde 용액에넣어후고정하고형태학적관찰을하였다. 뇌손상면적측정 Image J [freeware from the National Institutes of Health (http://rsb.info.nih.gov/ij/)] 8) 프로그램을이용하여, 충격속도와변형깊이에따라외상을가한대뇌반구에서피질과해마부위의손상면적을각각측정하였다. 측정방법은외상이가해진동측반구에서손상후보존된해마부위와보존된뇌피질의면적을측정하여외상이가해지지않은반대측반구의해당부위에대한백분율을계산한후 1% 에서뺀수치를손상면적으로하였다. 손상면적 =1-( 손상동측부위의보존된면적 / 손상반대측해당부위의면적 1) 결과 예비실험결과압축공기압에따른충격속도 Labscribe Data Acqusition Software를이용하여각각의압축공기압에서충격속도를측정한결과 5 psi 에서는평균 3.2±.1 m/s ( 이하 3.2 m/s), 8 psi에서는평균 3.9±.1 m/s ( 이하 3.9 m/s) 의충격속도가일정하게측정되었다. 외상후행동지수의변화 3개의실험군에서뇌외상후 1, 7, 14, 21, 28일째각각 ratarod test 와 mnss test 를통하여신경행동지수를측정한결과, 3.2 m/s의충격속도에비하여 3.9 m/s의충격속도의경우행동지수가더나빠지는것으로관찰되었으나, 개체간변이차이로인하여통계적으로유의미하지는않았다. 뇌외상이유발된 2군의실험동물모두외상후 1일째신경행동지수가가장감소하였고, 외상후 7일째부터신경행동학적기능이회복되기시작하여, 외상후 28일째에는뇌손상없이두개골절제술만시행한정상군과비슷하게신경행동지수가개선되는것을확인하였다 (Figure 1). 광학현미경소견 Cresyl violet 염색결과 3.2 m/s 의충격속도와 2. mm의변형깊이로뇌손상을가하였을때는주로뇌피 www.neurotrauma.or.kr 93
Animal Model of Controlled Cortical Injury 질부위가손상되었다. 그러나 3.9 m/s 의충격속도와 2. mm의변형깊이로뇌손상을가하였을때는뇌피질뿐아니라해마부위전체와치상회 (dentate gyrus) 의문 (hilus) 영역, 시상부위까지심하게손상됨을알수있었다 (Figure 2). 각각다른충격속도와변형깊이에따른신경행동지수변화 Rotarod motor test 3.2 m/s 와 3.9 m/s 의충격속도에서변형깊이를각각 1.5 mm, 2. mm, 2.5 mm로변화를주어뇌손상을가하고뇌외상후 1일째행동지수를측정한결과, 3.2 m/s 의충격속도에서는외상전에비하여각각평균 52.8%, 42.2%, 32.4% 의행동지수를나타냈으며, 3.9 m/s의충격속도에서는각각평균 41.7%, 35.2%, 22.8% 의행동지수를나타냈다. 같은충격속도에서변형깊이에대한행동지수를비교하였을때, 두충격속도모두 1.5 mm의변형깊이에비하여 2.5 mm 변형깊이에서 rotarod test 의행동지수가유의하게나빠졌음이확인되었다 [p<.5, one-way analysis of variance (ANOVA)]. 하지 만동일한변형깊이에서충격속도에따른손상정도를비교하였을때는통계상의유의미한차이를확인할수없었다 (Figure 3). Modified neurological severity score 3.2 m/s 와 3.9 m/s 의충격속도에서각각손상을가하는깊이를 1.5 mm, 2. mm, 2.5 mm로변화를주어뇌손상을가한결과, 3.2 m/s 의충격속도에서는각각평균 6.5점, 9.점, 1.1 점의행동지수를나타냈으며, 3.9 m/s 의충격속도에서는각각평균 8.2점, 9.7점, 1.1 점의행동지수를나타내었다. 동일한충격속도에서변형깊이에따른행동지수를비교하였을때, 각각의충격속도에서 1.5 mm의변형깊이보다 2.5 mm의변형깊이에서행동지수가나빠지는것으로보이나, 통계상의유의미한차이는없었다 (Figure 3). 형태학적변화 (2,3,5-triphenyl tetrazolium chloride monohydrate 염색결과 ) 실험동물에서적출된뇌조직절편을 TTC 염색한후 Image J 프로그램을사용하여각각의변수에따른조직 12 12 1 1 Rotarod test (%) A 8 6 4 2 Before TBI 1 day 7 day 8psi-2. mm Sham operation 14 day 21day 28 day 5psi-2. mm mnss B 8 6 4 2 Before TBI 1 day 7 day 8psi-2. mm Sham operation 14 day 21day 28 day 5psi-2. mm FIGURE 1. Neurological changes after controlled cortical impact in the rat traumatic brain injury model according to different impact pressure (velocity). A: Rotarod motor score. B: mn SS. mnss: modified neurological severity score, TBI: traumatic brain injury. FIGURE 2. Pathological findings (Cresy violet stain) show the different magnitude of C, H and DG injuries according to the different cortical impact pressure (velocity)(4 magnification). C: cerebral cortex, H: hippocampus, DG: dentate gyrus. 94 J Kor Neurotraumatol Soc 27;3:91-98
Hwa-Jung Kim, et al. 8 12 FIGURE 3. Results of neurobehavioral functional tests (A: Rotarod motor score, B: mnss) 1 day after TBI according to the various injury parameters. p<.5 in one-way ANOVA Turkey and Duncan method. mnss: modified neurological severity score, TBI: traumatic brain injury, ANOVA: analysis of variance. Rotarod test (%) A 7 6 5 4 3 2 1 3.2 m/s 3.9 m/s 3.2 m/s-1.5 mm 3.9 m/s-1.5 mm 3.2 m/s-2. mm 3.9 m/s-2. mm 3.2 m/s-2.5 mm 3.9 m/s-2.5 mm mnss B 1 8 6 4 2 3.2 m/s 3.9 m/s 3.2 m/s-1.5 mm 3.9 m/s-1.5 mm 3.2 m/s-2. mm 3.9 m/s-2. mm 3.2 m/s-2.5 mm 3.9 m/s-2.5 mm 5 psi-3.2 m/s 8 psi-3.9 m/s 2. mm 2. mm 1.5 mm 1.5 mm FIGURE 4. 2,3,5-triphenyltetrazolium chloride monohydrate (TTC) staining findings 1 day after TBI show the different magnitude of tissue injury according to the various injury parameters (coronal section with 2 mm thickness). TBI: traumatic brain injury. 2.5 mm 2.5 mm 의손상정도를뇌피질과해마부위에서각각측정하였다 (Figure 4). 뇌피질의경우, 3.2 m/s 의손상속도로 1.5 mm, 2. mm, 2.5 mm 변형깊이의뇌손상을가하였을때각각평균 31.5 %, 5.3 %, 56.7 % 의손상을보였으며, 3.9 m/s 의손상속도에서는각각평균 38.9%, 54.%, 61.2% 의손상을보였다 (Figure 5). 동일한손상속도에서변형깊이에대한뇌피질의손상면적을비교하였을때, 3.2 m/s, 3.9 m/s의손상속도모두에서 1.5 mm 의변형깊이에비하여 2. mm과 2.5 mm의변형깊이에서손상면적이유의미하게증가하였음을확인하였다. 해마의경우, 3.2 m/s의손상속도에서각각평균 36.7%, 44.1%, 83.9% 손상을보였으며, 3.9 m/s 의손상속도에서는각각평균 47.%, 85.9%, 96.7% 의손상을보였다. 동일한손상속도에서변형깊이에대한해마의손상면적을비교하였을때, 3.2 m/s의손상속도에서는 2.5 mm의변형깊이로뇌손상을주었을때만다른변형깊 www.neurotrauma.or.kr 95
Animal Model of Controlled Cortical Injury Injured area of cortex (%) 8 7 6 5 4 3 2 1 3.2 m/s 3.9 m/s Injured area of hippocampus (%) 12 1 8 6 4 2 3.2 m/s 3.9 m/s A 3.2 m/s-1.5 mm 3.9 m/s-1.5 mm 3.2 m/s-2. mm 3.9 m/s-2. mm 3.2 m/s-2.5 mm 3.9 m/s-2.5 mm B 3.2 m/s-1.5 mm 3.9 m/s-1.5 mm 3.2 m/s-2. mm 3.9 m/s-2. mm 3.2 m/s-2.5 mm 3.9 m/s-2.5 mm FIGURE 5. The ratio of injured volume of ipsilateral cortex and hippocampus compared to contralateral structures at various injury parameters. The volume was measured using Image J freeware from the National Institutes of Health (http://rsb.info.nih.gov/ij/). 8) A: Cerebral cortex. B: Hippocampus. p<.5 between different deformation depths with the same impact velocity in one-way ANOVA Turkey and Duncan method, p<.5 between different impact velocity with the same deformation depth in an independent samples t-test. ANOVA: analysis of variance. 이의실험군에비해손상면적이유의미하게증가하였으며, 3.9 m/s 의손상속도에서는 2. mm 혹은 2.5 mm 의변형깊이로뇌손상을가하였을때 1.5 mm의경우에비해손상면적이유의미하게증가됨을확인할수있었다 (p<.5, one-way ANOVA). 동일한변형깊이에서 3.2 m/s 와 3.9 m/s의손상속도에대한해마의손상면적을비교하였을때, 2 mm 변형깊이에서각각평균 44.1% 와 85.9% 가손상되어 3.2 m/s 의충격속도에비하여 3.9 m/s 의충격속도에서손상면적이유의미하게증가하였음을확인할수있었으나 (p<.5, independent samples t-test), 뇌피질의경우엔이와같은유의미한차이를확인할수없었다. 고찰 뇌외상은여러가지역학적인요소에의해일차적인세포손상이발생하면뇌혈류의변화, 국소적혹은전신적인염증반응, 산소운반능력과세포대사의변화같은다양한이차적인반응이일어나는병태생리를가지고있다. 17) 이러한복잡한병태생리때문에파킨슨씨병, 뇌경색과같은다른뇌질환과달리인간의뇌외상과기전이유사한재현성있는동물모델이확립되어있지않아뇌외상에대한깊이있는실험적연구를수행하는데어려움이있다. 7) 알려진여러뇌외상동물모델중뇌피질충격손상 (controlled cortical impact: CCI) 모델은뇌손상을유발하는변수를측정하여조절할수있다는장점때문에실험적연구에가장많이사용되고있으나, 저자들이문헌고찰을해본결과뇌손상을유발하는 변수들에따른뇌손상정도에대한보고는찾아볼수없었다. 본연구에서는뇌피질충격외상모델에서손상을유발하는여러가지변수들에따른실험동물의재현성있는기능적, 형태학적손상의정도를제시하였다는점에서의의를찾을수있을것이다. 뇌피질충격모델에서뇌손상을결정하는가장중요한요소는충격속도와변형깊이라고보고된바있다. 2,3) 문헌고찰상대부분 3 m/s 혹은 4 m/s 의충격속도와 2. mm의변형깊이를사용하여동물모델을만들었기때문에, 본연구에서는예비실험으로 3.2±.1 m/s의충격속도가산출되는공기압인 5 psi와 3.9±.1 m/s의충격속도가산출되는공기압인 8 psi의충격속도에서 2 mm의변형깊이로각각뇌손상을유발한뒤, 외상후 1일째부터일주일간격으로 4주째까지 rotarod motor score 를측정함으로써손상속도에따른손상정도를측정하였다. 두충격속도에대한운동지수를비교해본결과개체간변이때문에통계상유의미하지는않았으나외상후 1일째높은충격속도에서낮은충격속도에비해 rotarod motor score 가감소하였다. 또한 cresyl violet 염색을통한형태학적관찰결과압축공기압 5 psi 에서의충격속도에비해 8 psi에서의충격속도로뇌손상을유발할경우뇌피질뿐만아니라해마부위의치상회까지손상되는것을알수있었다. Smith 등 21) 도뇌피질충격손상후해마부위의 CA3 영역과치상회의문영역의세포에손상이가해진다고보고한바있어, 저자들은 3.2 m/s 와 3.9 m/s 의충격속도에서각각변형깊이를달리하여뇌손상을유발한후운동, 행동지수를관찰하고뇌피질과해마부위의손상면적을측정하여비교하였다. 96 J Kor Neurotraumatol Soc 27;3:91-98
Hwa-Jung Kim, et al. 본연구결과를정리해보면 3.2 m/s와 3.9 m/s의충격속도에서모두 rotarod motor score 와 mnss 가 1.5 mm 변형깊이와 2.5 mm 변형깊이에서만유의한차이를보였다. 뇌피질손상면적은 3.2 m/s와 3.9 m/s의충격속도에서모두 1.5 mm 변형깊이에비해 2. mm, 2.5 mm 변형깊이에서유의한차이를보였다. 따라서뇌외상실험동물에서뇌피질손상의정도를달리하면서운동, 행동지수의변화에대한연구를하고자할경우, 3.2 m/s (5 psi) 혹은 3.9 m/s (8 psi) 의충격속도에서는적어도변형깊이의차이를 1 mm 이상으로하여야만뇌외상의등급을나눌수있을것으로생각된다. 해마의경우는 3.2 m/s 의손상속도에서는 2.5 mm의변형깊이에서만다른변형깊이에비해유의한차이가나는 5% 이상의형태학적손상이관찰되었고, 3.9 m/s 의경우는 2. mm 이상의변형깊이에서 5% 이상의형태학적손상이관찰되었지만 2. mm와 2.5 mm 변형깊이에서의유의한차이는없었다. 또한뇌피질손상면적과달리 2. mm의변형깊이에서손상속도에따른손상면적의차이가유의하였다 (3.2 m/s의경우평균 44.1%, 3.9 m/s의경우평균 85.9%). 중증뇌외상환자의경우운동행동뿐아니라기억력감소, 판단력저하같은인지기능의장애가유발되는경우가흔하다. 1,16) 실험동물에서도해마의손상을동반하는뇌외상후 moris water maze test와 allothetic place avoidance task 등과같은평가를통해기억력, 인지기능의변화를측정한연구보고가있다. 4,7,19,22) Sanders 등 19) 은경증의뇌외상동물과중증의뇌외상동물을대상으로 moris water maze 실험을수행한결과, 중증의뇌외상동물이물속의안전한장소인 platform 을찾는시간이길어지는것을확인하여보고한바있다. 저자들은 moris water maze test 와같은해마손상으로인한기억력손상을측정하기위한관찰을하지는못하였지만, 본연구결과를종합해볼때충분한해마의손상을유도하기위해서는 3.2 m/s 의충격속도에서는변형깊이를 2.5 mm 이상, 3.9 m/s의충격속도에서 2. mm 이상의변형깊이를선택해야하고해마손상의정도를달리하기위해서는 2. mm의변형깊이에서손상속도를달리해야할것으로생각한다. 결론 본연구를통해뇌피질충격으로인한뇌외상실험동물에서손상속도와변형깊이에따라해부학적구조물의파괴와신경행동학적지수의감소정도가달라짐을 알수있었고, 손상속도가빠를수록, 변형깊이가깊을수록뇌손상이심해짐을확인하였다. 뇌손상으로인한해부학적손상과신경행동지수의변화의정도를달리하면서뇌손상의등급을나누기위해서는 3.2 m/s (5 psi), 3.9 m/s (8 psi) 의손상속도에서적어도 1 mm 이상의차이를두고변형깊이를결정해야할것으로생각한다. 특히, 해마부위까지손상을가하는중증실험모델을제작하고자하면 2. mm의변형깊이에서손상속도를달리해서뇌외상을생성해야손상정도를달리할수있을것으로기대된다. 중심단어 : 동물모델 뇌외상 뇌피질충격 손상정도. REFERENCES 1) Chen S, Pickard JD, Harris NG. Time course of cellular pathology after controlled cortical impact injury. Exp Neurol 182:87-12, 23 2) Choi SM, Suk JS, Kwon JT, Min BK, Kim YB, Hwang SN, et al. Development of upgraded cortical impact model (Part I: Mechanics). J Korean Neurosurg Soc 32:29-34, 22 3) Choi SM, Suk JS, Min BK, Hwang SN, Kim YB, Kim JH. Development of upgraded cortical impact model (Part II: Functional outcome). J Korean Neurosurg Soc 32:458-462, 22 4) Cimadevilla JM, Wesierska M, Fenton AA, Bures J. Inactivating one hippocampus impairs avoidance of a stable roomdefined place during dissociation of arena cues from room cues by rotation of the arena. Proc Natl Acad Sci U S A 98:3531-3536, 21 5) Dixon CE, Clifton GL, Lighthall JW, Yaghmai AA, Hayes RL. A controlled cortical impact model of traumatic brain injury in the rat. J Neurosci Methods 39:253-262, 1991 6) Dixon CE, Lyeth BG, Povlishock JT, Findling RL, Hamm RJ, Marmarou A, et al. A fluid percussion model of experimental brain injury in the rat. J Neurosurg 67:11-119, 1987 7) Fujimoto ST, Longhi L, Saatman KE, Conte V, Stocchetti N, McIntosh TK. Motor and cognitive function evaluation following experimental traumatic brain injury. Neurosci Biobehav Rev 28:365-378, 24 8) Kirton A, Shroff M, Visvanathan T, deveber G. Quantified corticospinal tract diffusion restriction predicts neonatal stroke outcome. Stroke 38:974-98, 27 9) Lacza Z, Horváth E, Busija DW. Neural stem cell transplantation in cold lesion: a novel approach for the investigation of brain trauma and repair. Brain Res Brain Res Protoc 11:145-154, 23 1) Levin HS, Eisenberg HM, Wigg NR, Kobayashi K. Memory and intellectual ability after head injury in children and adolescents. Neurosurgery 11:668-673, 1982 11) Li Y, Chen J, Chen XG, Wang L, Gautam SC, Xu YX, et al. Human marrow stromal cell therapy for stroke in rat: Neurotrophins and functional recovery. Neurology 59:514-523, 22 12) Lighthall JW, Goshgarian HG, Pinderski CR. Characterization of axonal injury produced by controlled cortical impact. J Neurotrauma 7:65-76, 199 13) Lu D, Li Y, Mahmood A, Wang L, Rafiq T, Chopp M. Neural and marrow-derived stromal cell sphere transplantation in a rat model of traumatic brain injury. J Neurosurg 97:935-94, 22 www.neurotrauma.or.kr 97
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